Elastic-fluid turbine.



C. G. CURTIS. ELASTIC FLUID TURBINE.

APYLICATION TILED AUG. 24, 1905.

Patented June 27, 1911.

5 SHEETS-SHEET 1 Witnesses c. e. mums. I ELASTIC FLUID TURBINE. LE'YLICATION TILED AUG. 24, 1905.

996,317, Patented Juiie 27,1911

5 SHEETS-SEES! 2.

C. G. CURTIS; ELASTIC FLEID TURBINE. APPLICATION nun M1024, mos.

996,317. v Patented June 27, 1911. I

(((((( & (WK m Witnesses \4 A Inventor c. G. CURTIS. I

- ELASTIC mm) TURBINE. g APPLIGATIOF FILED AUG. :34. 1905: 996,317, 7 Patented June 27, 1911. 5 BHEETB-BHEET 4. Y

' Witnesses: Inventor 1 E Attorney c.- e. cnn'ns.

ELASTIC FLUID TURBINE. AYPLIOATIOK FILED AUG. 24, 1905.

. Patented June 27,1911. 5 SKBETS-SHBET 5.

Inventor 0X01? .42? 7 W5! UNITED STATES ra rnn'r OFFICE.

', cnamms a. CURTIS, OF NEW YORK, N. Y., ASSIGNOR 'ro GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

996 3 a; Specification ct Letters Patent. 1 tented U110 27, 1911. Application filed August 24, 1905. Serial No. 275,623.

To all whom it may concern. as will be necessary in order to secure the l t it known that I, CHARLES G. CURTIS, a proper increase of space to accommodate the ich of the United States, and aresident increased bulk of steam, but in order to of the borough of Manhattan, city, county, permit of a greater angle of entrance and 5 and StsiIc of New York, have invented adiscbarge in the buckets, as would be the 60 certain new and useful Improvement in case if all of the last few rows of buckets El=istic-Fl1iid I urbines, of which the followwere of thesame height. The objection to is a description. having the first few rows of buckets of the mic object I have in View is the producproper theoretical depth in order to provide tion of a turbine, which will be of high for the bulk of steamjpassing through is 5 etlicicucy and of small bulk. and which will that if the depth of the buckets for the ini particularly applicable for marine purtel-mediate portion of the turbine be propposcs. although itmay be used for other erly proportioned for .corrcct theoretical purposes. I conditions the depth for the first few rows i 'l u tnrbine is preferably of the drum y'awill be exceedingly small, and in fact may ricty, although such form is not essential, not cxcced the actual clearance between the and it may be of the annular or forccdfiow fixed and movable surfaces. lhis objection variety, although it may be modified by commay be overcome by forming the. first rows bining it in the higher stages with a turbine of buckets to operate upon the jet type and 30 orturbincs of jet form, in which only a prousing only a portionot the periphery of port-ion of the periphery of each wheel is each wheel at a given time, and so construct actcd upon at one time by the elastic fluid. ed that the wheels may be arranged in sepalncualcr to secure the maximum of cllirate casings, or if dcsircd, in groups of a tlcncy i provide a turbine with buckets all small number of wheels, each group within a 25 upon the same angle, and workingwith equal casing, the several casings to be connected velocities, and developing equal energy in together by passages properly proportioned each wheel and in which the. buckets into accommodate the increased bulk of steam, CIXHSE in depth toward the exhaust in such and to properly direct it over an increasrelation as to develop equal velocities and ingly larger portion of the periphery of the equal energies in each row o'it' buckets, and wheels as it travels in the, direction of the provide a passageway for the increased bulk exhaust. of the steam as it expands toward the exin the drawings Figure 1 shows the curve haust- This increased depth is gradual and of volumes in a turbine having 2.) rows of in order to secure the maximum cilicicncy moving buckets and 24 intermediates, the. should be made upon the line ofa curve buckets being all of the same angle and 9) which may be determined by calculation. working with equal velocities, and arranged Such a: form of turbine will produce the to develop equal energy in each stage. Fig. greatestciliciency. but itmay boopcn to the 2 shows a diagrammatical view of buckcls jection of having too great a depth of and intcrmcdiatesof the same numbcr.show-- uckets for the last, few stages, and also in ing the increased depth of the buckets tohaving too slight. a depth of buckets for the ward the exhaust to accommodate tho flint stages. The practical trouble with the increased bulk of steam due to expansion, exhaust end of the turbine may be overcome Fig. 3 shows in-diagrammatical form a turiv lugs-easing the angle of entrance and dis binc having 19 rows of buckets, the wheel charge of the wheel and intermediate bnci' of the first eight rows being arranged in cts so as to compensate for the decrease in pairs to form jct turbines, and the wheels height; which will be necessary in order to of the rcmaining eleven rows being arranged have the depth of the buckets conform to in the form of a singleannular turbine, most the vmlume curve. The last few buckets of the buckets being of increasing, depth toward the exhaust can be of uniform depth, toward the exhaust, the last three rows of 5 Q the angle. of entrance and discharge being buckets being of equal depth, but with ini in such proportion as to provide for the increasing angles of entrance and delivery. rcaseid bulk of fluid. If desired the depth Fig. 4 illustrates a development of theturof the buckets of the last few stages may be bine similar to that illustrated in Fig. 3, gmdrsally increased, not. so much, however, with the addition of nozzles for each stage in the jet. turbines and a nozzle for the annular turbine. Fig. is a development 01. the turbine illustrated in Fig. 4, showing the increased angles of entrance and discharge 5 of both wheels and intermcdiates and Fig. 0 is a longitudinal sectional view of 'an cmbodiment-of the invention showing a turbine similar to that developed in Fig. 5.

In all the views like arts are designated 10 by the same reference 0 aracters.

In Fig. l the line (2-4) reprcsents'the energy of foot pounds developed per pound of steam. 0 represents the moving vanes and (Z the fixed parts or'nozzles. The line 0-) 1 represents the curve of volumes in cubic feet. For clearness of illustration the energy of foot pounds per pound is presumed to be 10,000 foot pmmds foreach row of buckets. \Vorking on an expansion of from.

175 pounds to 1.10 pounds absolute and based on a re'e'vaporation of 50 per cent. of

condensed increment for each expansion the pressure within the steam passages at the itl'erent stages would be as shown in Fig.

1. The volumes would increase from about three cubic feet per pound in the first stage to about 300 for the 25th, and the curve of volume would be a steadily rising one.

In theM-urbine illustrated in Fig. 2 the depths of wheel buckets and nozzle buckets are regulated in accordance with the curve illustrated in Fig. 1. Instead of having the buckets secured to a drum of cylindrical form such as would be the case if they were I made directly. in accordance with the chart illustrated in Fig. 1, the drum is formed upon a 'curte calculated to be the same as that of the upper, outer or free edges of the buckets, so that "a line drawn through 40 the center of each bucket will be straight and parallel to the shaft of the drum. By this means the size of the turbine will be reduced and will be smaller than if a cylindrical drum were used. Irt a turbine constructed as shown in Figs. 1 and 2 the last few rows of buckets would be undesirably deep. In Fig. 3 a means is shown for avoiding this, in which the last three rows of buckets are of equal depth. In order to providefor the-increased .zlume of steam due to expansion, the angles of entrance and discharge of these buckets are increased. As already described in connection with v Figs. 1 and 2, the buckets it. the first few rows of the turbine will be undesirably low, and in a. full sized machine their depth may not exceed the actual clearance between the fixed and moving parts. In order to avoid this objection the first rows of buckets may be made of greater depth, and the nozzles may be so arranged as to discharge 'upon but a port-ion of the periphery of each wheel at the same time. The depth of 'the buckets and areas of nozzles discharging upon them will be properly calculated so as to provide the ropcr area through which the steam woul pass.

In Figs. 3 and 4 the first eight rows of buckets are arranged in the form of a jet turbine, two rows of wheels heinoarranged '20 in each set. In Fig. 4 the development of the turbine illustrated in Fig. 3 is iilus-' trated. Here the first eight rows of wheels are arranged in sets of two, the nozzles and wheel buckets having the same angles of entrance and delivery. The nozzles and intermediate nozzles are arranged in seg-- ments of a circle, the segments increasing in depth in successive setstoward the exhaust. The fourth set discharges in the annular fiow turbine, in which the entire periphery' is utilized. The first row of buckets"of the annular flow turbine will under these conditions have a reasonable depth so "(a as to be efficient. .This depth will increase 861 gradually and in accordance with the curve illustrated in Fig. 1 until its dspth becomes the niaximum practicable, when the buckets may be of uniform depth and the angles of entrance and discharge increased.

In Fig. 5 it represents a row of wheel j buckets and z' a row of nozzles of an em bocliment of the invention which is intended only to be an illustrative example. These have the same angles of exit and entrance 96 as of the preceding rows of buckets in the turbine. The entrance of the wheels as shown is 37 degrees and the angle of exit' is 22 degrees. The angle of entrance of the nozzles is 60' degrees and the angle of exit 100 is 20 degrees. .This is calculated for a tur-" 1 him: having a peripheral speed of 350 feetper second, and 1400 feet. er second steam velocity, with a. nozzle with an efiiciency of? 92.5 percent. In the three'succeedingstagcsl10o 7 it is shown that the angles of entrance and exit of the wheels and nozzleslincrcase. is-

the 17th wheel and k the nozzle precedm it. I is the 18th wheel and m' the nozzle prey ceding it, n the 19th whcel and o the mi: l 10 zle precedingit. As shown the angles of entrance and dischal e of these assagcs are as follows: In the 1 th wheel t e angle of entrance is 47 degrees and the angle of disthis, the angle of entrance is 60 degrees an the an le of discharge is 25 degrees. In the 18t wheel the angle of entrance is 61" degrees and the angle of discharge is 36 degrees; for the nozzle preceding it the angle of entrance is 66 degrees and the angle of discharge is 33 degrees. In the 19th wheel the angle of entrance is 78 degrees and the angle of discharge 46 degrees; .for

barge 28 degrees; for the nozzle prcccdin the nozzle preceding it. the angle of entrance 32 -5. is 74 degrees and the angle of discharge- 42 degrees. h In the exam 16 illustrated all the angled H of dischar e 0 the nozzles preceding wheel n are 20 egrecs and their entrance angles 1 1 buckets of each wheelpneceding nozzle 2'- is.

are 60 degrees, and the entrance angle of the 37 degrees and its discharge is 22 degrees.

A structural form of turbine is shown in Fig. 6. This turbine is apractical form of that developed in Fig. 5. Four jet stages A, B, C, D, and one annular stage E at the low pressure end of the turbine are shown, all ha'ving movable buckets c and fixed intermediate nozzles (I, there being two sets of the former and one set of the alter in each of the high pressure sta e-s. The

annular stage has eleven sets 0? moving.

buckets c and ten sets of fixed intermediate nozzles 03, the depths of the first eight sets of moving buckets being gradually increased upon the curve shown in Figs. 1 and 2, and the remaining three sets of moving buckets bein all of the same depth, but becoming gra ually flatter, as described in connection with Fig. 5. Any form of wheels or casing can be used, a convenient form being illustrated and being quite similar to that (lisclosed in my co-pending application for atent Serial No. 114,357, filed July 5, 1902. YVheels F and diaphragins G similar to those disclosed in that application are illustrated in Fig. 6. A shaft H supports the wheels and a casing I incloscs the wheels and dia'phragms and supports the intermediate nozzles.

Having now described my invention what I claim as new and desire to secure by Lette'ts Patent is:

1. In an elastic fluid turbine, the combination of wheel buckets and fixed nozzles,

a ortion of the wheel buckets and nozzles being all on the same angle and increasing in depth toward the exhaust. in such a-relation as to develop equal velocities and energies in each row of buckets, and a portion of the wheel buckets and nozzles not increasing in depth in such relation, but having the angles of entrance and exitincreased, so as to provide a passageway of the proper size for the increased bulk of tin elas ic fluid as it expands toward the er'naust.

vequal velocities and energies in each row of buckets, and a portion of the wheel buckets and nozzles not increasing indepth iii such relation, but having the angles of entrance and exit increased so as to provide a passageway of the proper size for the increased bulk of the elastic fluid as it expands toward the exhaust, in combination with high ressure jet stages. 7

3. iii an elastic fluid turbine, the combination of wheel buckets and fixed nozzles, a ortion of the wheel buckets and nozzles belng all on the same angle and providing for progressive increase of dimensions of the expanding fluid solely bv increase of depth toward the exhaust, an a portion of'the wheel buckets and nozzles not increasing in depth in such relation bnt providing, wholly or in part, for the increased bulk of fluid by having the angles of entrance and exit: increased so as to provide a passageway of proper size.

4. In an elastic fluid turbine, the eombi nation of wheel buckets and fixed nozzles, a portionof the wheel buckets and nozzles being all on the same angle and providing for progressive increase 9 dimensions of the expanding fluid solely b increase of depth toward the exhaust, and a portion of the wheel buckets and nozzles not increasing in depth in such relation but providing, wholly or in part, for the increa ed bulk of fluid by having the angles of entrance and exit increased so as to provide a passagewa of proper size, in combination with big pressure jet stages,

'lhis specification signed and witnessed this 18th day of August, 1905.

CHARLES G. CURTIS.

\Vitnesscs:

J no. Rom. Tarpon, Annnnr LOUIS SMITH. 

